Tag Archives: cardiovascular disease

Do Nuts Help Or Hurt Cholesterol Levels?

Mixed Nuts Improve Diabetes, Too

Mixed Nuts Improve Diabetes

Most of the diets I recommend to my patients include nuts because they are so often linked to improved cardiovascular health in scientific studies. Walnuts are associated with reduced risk of type 2 diabetes in women, and established type 2 diabetics see improved blood sugar control and lower cholesterols when adding nuts to their diets.

Nut consumption lowers total and LDL cholesterol levels, and if triglycerides are elevated, nuts lower them, too. Those changes would tend to reduce heart disease.

Conner Middelmann-Whitney has a good nutty article at Psychology Today.

Steve Parker, M.D.

Reference: Joan Sabaté, MD, DrPH; Keiji Oda, MA, MPH; Emilio Ros, MD, PhD. Nut Consumption and Blood Lipid Levels: A Pooled Analysis of 25 Intervention Trials. Archives of Internal Medicine, 2010, Vol. 170 No. 9, pp 821-827. Abstract:

Background  Epidemiological studies have consistently associated nut consumption with reduced risk for coronary heart disease. Subsequently, many dietary intervention trials investigated the effects of nut consumption on blood lipid levels. The objectives of this study were to estimate the effects of nut consumption on blood lipid levels and to examine whether different factors modify the effects.

Methods:  We pooled individual primary data from 25 nut consumption trials conducted in 7 countries among 583 men and women with normolipidemia and hypercholesterolemia who were not taking lipid-lowering medications. In a pooled analysis, we used mixed linear models to assess the effects of nut consumption and the potential interactions.

Results:  With a mean daily consumption of 67 g of nuts [about 2 ounces or 2 palms-ful], the following estimated mean reductions were achieved: total cholesterol concentration (10.9 mg/dL [5.1% change]), low-density lipoprotein cholesterol concentration (LDL-C) (10.2 mg/dL [7.4% change]), ratio of LDL-C to high-density lipoprotein cholesterol concentration (HDL-C) (0.22 [8.3% change]), and ratio of total cholesterol concentration to HDL-C (0.24 [5.6% change]) (P < .001 for all) (to convert all cholesterol concentrations to millimoles per liter, multiply by 0.0259). Triglyceride levels were reduced by 20.6 mg/dL (10.2%) in subjects with blood triglyceride levels of at least 150 mg/dL (P < .05) but not in those with lower levels (to convert triglyceride level to millimoles per liter, multiply by 0.0113). The effects of nut consumption were dose related, and different types of nuts had similar effects on blood lipid levels. The effects of nut consumption were significantly modified by LDL-C, body mass index, and diet type: the lipid-lowering effects of nut consumption were greatest among subjects with high baseline LDL-C and with low body mass index and among those consuming Western diets.

Conclusion:  Nut consumption improves blood lipid levels in a dose-related manner, particularly among subjects with higher LDL-C or with lower BMI.

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Filed under Heart Disease, nuts

FDA Reversal: Rosiglitazone DOES NOT Pose Cardiovascular Risk

Rosiglitazone is a type 2 diabetes drug in the thiazolidinedione class. In 2011, the U.S. Food and Drug Administration determined that rosiglitzone posed a substantial risk for causing premature cardiovascular disease such as heart attacks. The agency greatly restricted prescribers, essentially killing the drug’s sales in the U.S. In November, the FDA took another look at the data and decided the risk was minimal or non-existent.

Dr. Steven Nissen of the Cleveland Clinic is on record as opposing the new change.

A lot of personal injury lawyers will be disappointed in the change unless they’ve already settled their cases out of court.

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Filed under Drugs for Diabetes

Is Low-Carb Killing Swedish Women?

MPj04384870000[1]A recent Swedish study suggests that low-carbohydrate/high protein diets increase the risk of cardiovascular disease in women.  I’m not convinced, but will keep an eye on future developments.  This is a critical issue since many women eat low-carb/high protein for weight loss and management.

Researchers followed 43,000 women, 30-49 years of age at enrollment, over the course of 16 years.  In that span, they had 1270 cardiovascular events: ischemic heart disease (heart attacks and blocked heart arteries), strokes, subarachnoid hemorrhages,  and peripheral arterial disease.  Food consumption was estimated from a questionnaire filled out by study participants at the time of enrollment (and never repeated).

In practical terms, … a 20 gram decrease in daily carbohydrate intake and a 5 gram increase in daily protein intake would correspond to a 5% increase in the overall risk of cardiovascular disease.

So What?

To their credit, the researchers note that a similar analysis of the Women’s Health Study in the U.S. found no such linkage between cardiovascular disease and low-carb/high protein eating.

The results are questionably reliable since diet was only assessed once during the entire 16-year span.

I’m certain the investigators had access to overall death rates.  Why didn’t they bother to report those?  Your guess is as good as mine.  Even if low-carb/high protein eating increases the rate of cardiovascular events, it’s entirely possible that overall deaths could be lower, the same, or higher than average.  That’s important information.

I don’t want to get too far into the weeds here, but must point out that the type of carbohydrate consumed is probably important.  For instance, easily digested carbs that raise blood sugar higher than other carbs are associated with increased heart disease in women.  “Bad carbs” in this respect would be simple sugars and refined grains.

In a 2004 study, higher carbohydrate consumption was linked to progression of blocked heart arteries in postmenopausal women.

It’s complicated.

Steve Parker, M.D.

PS: I figure Swedish diet doctor Andreas Eenfeldt would have some great comments on this study, but can’t find them at his blog.

Reference: Lagiou, Pagona, et al.  Low carbohydrate-high protein diet and incidence of cardiovascular diseases in Swedish women: prospective cohort study.  British Medical Journal, June 26, 2012.  doi: 10.1136/bmj.e4026

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Filed under Carbohydrate, coronary heart disease, Heart Disease, Protein

Is It More Important To Be Fit, Or Healthy Weight?

Men live longer if they maintain or improve their fitness level over time, according to research out of the Cooper Clinic in Dallas, Texas.  Part of that improved longevity stems from reduced risk of death from cardiovascular disease (e.g., heart attack and stroke). 

Compared with men who lose fitness with aging, those who maintained their fitness had a 30% lower risk of death; those who improved their fitness had a 40% lower risk of death.  Fitness was judged by performance on a maximal treadmill exercise stress test.

Body mass index over time didn’t have any effect on all-cause mortality but was linked to higher risk of cardiovascular death.  The researchers, however, figured that losses in fitness were the more likely explanation for higher cardiovascular deaths.  In other words, as men age, it’s more important to maintain or improve fitness than to lose excess body fat or avoid overweight.

Steve Parker, M.D.

Reference: Lee, Duck-chul, et al.  Long-term effects of changes in cardiorespiratory fitness and bodly mass index on all-cause and cardiovascular disease mortality in menCirculation, 124 (2011): 2,483-2,490

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Filed under Exercise, Longevity, Overweight and Obesity

Finally Settled: Alcohol Consumption Linked to Lower Rates of Death and Heart Attack

Canadian and U.S. researchers report that moderate alcohol consumption seems to reduce 1) the incidence of coronary heart disease, 2) deaths from coronary heart disease, and 3) deaths from all causes.  Reduction of death from all causes is a good counter-argument to those who say alcohol is too dangerous because of deaths from drunk driving, alcoholic cirrhosis, and alcohol-related cancers such as many in the esophagus. 

Remember, we’re talking here about low to moderate consumption: one drink a day or less for women, two drinks or less a day for men.  That’s a max of 12.5 grams of alcohol for women, 25 g for men.  No doubt, alcohol can be extremely dangerous, even lethal.  I deal with that in my patients almost every day.  Some people should never drink alcohol.

The recent meta-analysis in the British Medical Journal, which the authors say is the most comprehensive ever done, reviewed all pertinent studies done between 1950 and 2009, finally including 84 of the best studies on this issue.  Thirty-one of these looked at deaths from all causes.

Compared with non-drinkers, drinkers had a 25% lower risk of developing coronary heart disease (CHD) and death from CHD.  CHD is the leading cause of death in develop societies.

Stroke is also considered a cardiovascular disease.  Overall, alcohol is not linked to stroke incidence or death from stroke.  The researchers did see strong trends toward fewer ischemic strokes  and more hemorrhagic strokes (bleeding in the brain) in the drinkers.  So the net effect was zero. 

Compared with non-drinkers, the lowest risk of death from any cause was seen in those consuming 2.5 to 14.9 g per day (one drink or less per day), whose risk was 17% lower.  On the other hand, heavy drinkers (>60 g/day) had 30% higher risk of death. 

In case you’re wondering, the authors didn’t try to compare the effects of beer versus wine versus distilled spirits. 

On a related note, scientists at the Medical University of South Carolina found that middle-aged people who took up the alcohol habit had a lower risk of stroke and heart attack.  Wine seemed to be more effective than other alcohol types.  They found no differences in overall death rates between new drinkers persistent non-drinkers, perhaps because the study lasted only four years and they were following only 442 new drinkers.  

This doesn’t prove that judicious alcohol consumption prevents heart attacks, cardiac deaths, and overall deaths.  But it’s kinda lookin’ that way.

Steve Parker, M.D.

 References:  Ronksley, Paul, et al.  Association of alcohol consumption with selected cardiovascular disease outcomes: a systematic review and meta-analysisBritish Medical Journal, 2011;342:d671    doi: 10.1136/bmj.d671

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Filed under Alcohol, coronary heart disease

Exercise, Part 1: Exercise Postpones Death

Earlier this month, many folks made New Years’ resolutions to start exercising in conjunction with their other resolution to lose excess weight. I’ve got bad news for them.

Exercise is overrated as a pathway to major weight loss.

Sure, a physically inactive young man with only five or 10 pounds (2 to 4 kg) to lose might be able to do it simply by starting an exercise program. That doesn’t work nearly as well for women. The problem is that exercise stimulates appetite, so any calories burned by exercise tend to be counteracted by increased food consumption.

"Should I go with aerobic or strength training....?"

On the other hand, exercise is particularly important for diabetics and prediabetics in two respects: 1) it helps in avoidance of overweight, especially after weight loss, and 2) it helps control blood sugar levels by improving insulin resistance, perhaps even bypassing it.

Even if it doesn’t help much with weight loss, regular physical activity has myriad general health benefits. First, let’s look at its effect on death rates.   

EXERCISE PREVENTS DEATH

As many as 250,000 deaths per year in the United States (approximately 12% of the total) are attributable to a lack of regular physical activity. We know now that regular physical activity can prevent a significant number of these deaths.

Exercise induces metabolic changes that lessen the impact of, or prevent altogether, several major illnesses, such as high blood pressure, coronary artery disease, diabetes, and obesity. There are also psychological benefits. Even if you’re just interested in looking better, awareness of exercise’s other advantages can be motivational.

Exercise is defined as planned, structured, and repetitive bodily movement done to improve or maintain physical fitness.

Physical fitness is a set of attributes that relate to your ability to perform physical activity. These attributes include resting heart rate, blood pressure at rest and during exercise, lung capacity, body composition (weight in relation to height, percentage of body fat and muscle, bone structure), and aerobic power.

Aerobic power takes some explanation. Muscles perform their work by contracting, which shortens the muscles, pulling on attached tendons or bones. The resultant movement is physical activity. Muscle contraction requires energy, which is obtained from chemical reactions that use oxygen. Oxygen from the air we breathe is delivered to muscle tissue by the lungs, heart, and blood vessels. The ability of the cardiopulmonary system to transport oxygen from the atmosphere to the working muscles is called maximal oxygen uptake, or aerobic power. It’s the primary factor limiting performance of muscular activity.

Aerobic power is commonly measured by having a person perform progressively more difficult exercise on a treadmill or bicycle to the point of exhaustion. The treadmill test starts at a walking pace and gets faster and steeper every few minutes. The longer the subject can last on the treadmill, the greater his aerobic power. A large aerobic power is one of the most reliable indicators of good physical fitness. It’s cultivated through consistent, repetitive physical activity.

Physical Fitness Effect on Death Rates

Regular physical activity postpones death.

Higher levels of physical fitness are linked to lower rates of death primarily from cancer and cardiovascular disease (e.g., heart attacks and stroke). What’s more, moving from a lower to a higher level of fitness also prolongs life, even for people over 60.

Part 2 of this series will cover all the other health benefits of exercise. Part 3 will outline specific exercise recommendations, such as the type and duration of activity.

Steve Parker, M.D.

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THIS Is Why I Love the Mediterranean Diet

Italian researchers reviewed the medical/nutrition literature of the last three years and confirmed that the Mediterranean diet 1) reduces the risk of death, 2) reduces  heart disease illness and death, 3) cuts the risk of getting or dying from cancer, and 4) diminishes the odds of developing dementia, Parkinsons disease, stroke, and mild cognitive impairment.

These same investigators published a similar meta-analysis in 2008, looking at 12 studies.  Over the ensuing three years (as of June, 2010), seven new prospective cohort studies looked at the health benefits of the Mediterranean diet.  The report at hand is a combination of all 19 studies, covering over 2,000,000 participants followed for four to 20 years.  Nine of the 19 Mediterranean diet studies were done in Europe.

The newer studies, in particular, firmed up the diet’s protective effect against stroke, and added protection against mild cognitive impairment.

So What?

The Mediterranean diet: No other way of eating has so much scientific evidence that it’s healthy and worthy of adoption by the general population.  Not the DASH diet, not the “prudent diet,” not the American Heart Association diet, not vegetarian diets, not vegan diets, not raw-food diets, not Esselstyne’s diet, not Ornish’s diet, not Atkins diet, not Oprah’s latest diet, not the Standard American Diet, not the  . . . you name it. 

Not even the Low-Carb Mediterranean Diet.

Just as important, the research shows you don’t have to go full-bore Mediterranean to gain a health and longevity benefit.  Adopting  just a couple Mediterranean diet features yeilds a modest but sigificant gain.  For a list of Mediterranean diet components, visit Oldways or the Advanced Mediterranean Diet website. 

Steve Parker, M.D.

Reference:  Sofi, Francesco, et al.  Accruing evidence about benefits of adherence to the Mediterranean diet on health: an updated systematic review and meta-analysis.  American Journal of Clinical Nutrition, ePub ahead of print, September 1, 2010.  doi: 10.3945/ajcn.2010.29673

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Filed under coronary heart disease, Health Benefits, Mediterranean Diet